UFC 15 was headlined by a Heavyweight Championship bout between Maurice Smith and Tank Abbott. Abbott was brought in as a last-minute replacement for Dan Severn, who could not fight because of an injured hand.

UFC 15 also featured a Superfight between Randy Couture and Vitor Belfort, a Heavyweight Tournament, and two alternate bouts. The show also marked the last event to feature Bruce Beck, who had been the main play-by-play announcer starting with UFC 4.

Collision Course marked a major change in the UFC's rules, with limitations set on permissible striking areas. Headbutts, groin strikes, strikes to the back of the neck & head, kicks to a downed opponent, small joint manipulation, pressure point strikes, and hair pulling all became officially illegal.